The United States Food and Drug Administration has approved the use of recombinant bovine somatotropin (bST) in dairy cows and the hormone has widespread use. The use of bST has sparked a nationwide controversy regarding economic, health and political issues. The controversy has led some dairy product distributors to mark their products with claims that the products are bST free or that the cows used to produce the milk were not treated with bST. However, currently there is no simple test for determining whether milk has come from an animal treated with the hormone.
In addition, there is presently no test to predict the production response of cows to bST treatment. Therefore, the dairy manager may be wasting resources administering bST to cows which are not responding to the hormone.